US urges North Korea to grant amnesty, immediate release for...... for American sentenced to 15 years. The U.S. called Thursday for North Korea to grant amnesty and immediately release a Korean-American sentenced to 15 years' hard labour for "hostile acts" against the state.

Kenneth Bae, 44, a Washington state man described by friends as a devout Christian and a tour operator, is at least the sixth American detained in North Korea since 2009. The others eventually were deported or released without serving out their terms, some after trips to Pyongyang by prominent Americans, including former presidents Bill Clinton and Jimmy Carter.

Analysts say Bae's sentencing could be an effort by Pyongyang to win diplomatic concessions in the ongoing standoff over its nuclear program. But there was no immediate sign a high-profile envoy was about to make a clemency mission to the isolated nation which has taken an increasingly confrontational stance under its young leader Kim Jong Un, who has the power to grant special pardons under the North's constitution.

State Department spokesman Patrick Ventrell said the U.S. was still seeking to learn the facts of Bae's case. He said the Swedish Embassy in Pyongyang, which handles consular matters there for the U.S., did not attend Tuesday's Supreme Court trial and that there hasn't been transparency in the legal proceedings.

"There's no greater priority for us than the welfare and safety of U.S. citizens abroad, and we urge the DPRK authorities to grant Mr. Bae amnesty and immediate release," Ventrell told a news conference, referencing the socialist country's formal title, the Democratic People's Republic of Korea.

North Korea has faced increasing international criticism over its weapons development. Six-nation disarmament talks involving the Koreas, the United States, Japan, China and Russia fell apart in 2009. Several rounds of U.N. sanctions have not encouraged the North to give up its small cache of nuclear devices, which Pyongyang says it must not only keep but expand to protect itself from a hostile Washington. Tensions have escalated since it conducted its third nuclear test since 2006 in February.

Pyongyang's tone has softened somewhat recently, following weeks of violent rhetoric, including threats of nuclear war and missile strikes. There have been tentative signs of interest in diplomacy, and a major source of North Korean outrage — annual U.S.-South Korean military drills — ended Tuesday.

Patrick Cronin, a senior analyst with the Washington-based Center for a New American Security, called Bae's conviction "a hasty gambit to force a direct dialogue with the United States."

"While Washington will do everything possible to spare an innocent American from years of hard labour, U.S. officials are aware that in all likelihood the North Korean regime wants a meeting to demonstrate that the United States in effect confers legitimacy on the North's nuclear-weapon-state status," Cronin said in an email.

White House spokesman Jay Carney told reporters travelling aboard Air Force One en route to Mexico that if North Korea is interested in discussion, they should live up to their obligations under the six-party talks.

"Thus far, as you know, they have flouted their obligations, engaged in provocative actions and rhetoric that brings them no closer to a situation where they can improve the lot of the North Korean people or re-enter the community of nations," Carney said.

The state-run Korean Central News Agency announcement of Bae's sentencing came just days after it reported Saturday that authorities would soon indict and try him. It referred to Bae as Pae Jun Ho, the North Korean spelling for his Korean name. The State Department had appealed Monday for his release on humanitarian grounds.

Bae, from Lynnwood, Wash., was arrested in early November in Rason, a special economic zone in North Korea's far northeastern region bordering China and Russia, state media said. The exact nature of Bae's alleged crimes has not been revealed.

"Kenneth Bae had no access to a lawyer. It is not even known what he was charged with," the human rights group Amnesty International said in a statement. "Kenneth Bae should be released, unless he is charged with an internationally recognizable criminal offence and retried by a competent, independent and impartial court."

Ventrell said the Swedish embassy's most recent access to Bae was last Friday. It has only had a handful of brief opportunities to see him since he was arrested in early November, according to U.S. officials.

Friends and colleagues say Bae was based in the Chinese border city of Dalian and travelled frequently to North Korea to feed orphans. Bae's mother in the United States did not answer calls seeking comment Thursday.

There are parallels to a case in 2009. After Pyongyang's launch of a long-range rocket and its second underground nuclear test that year, two American journalists, Laura Ling and Euna Lee, were sentenced to 12 years of hard labour after sneaking across the border from China.

They later were pardoned on humanitarian grounds and released to Clinton, who met with then-leader Kim Jong Il. U.S.-North Korea talks came later that year.

In 2011, Carter visited North Korea to win the release of imprisoned American Aijalon Gomes, who had been sentenced to eight years of hard labour for crossing illegally into the North from China.

On Thursday, Carter's press secretary, Deanna Congileo, said by email that the former president has not had an invitation to visit North Korea and has no plans to visit.

Korean-American Eddie Jun was released in 2011 after Robert King, the U.S. envoy on North Korean human rights, travelled to Pyongyang. Jun had been detained for half a year over an unspecified crime.

Jun and Gomes are also devout Christians. While the North Korean Constitution guarantees freedom of religion, in practice only sanctioned services are tolerated by the government.

U.N. and U.S. officials accuse North Korea of treating opponents brutally. Foreign nationals have told varying stories about their detentions in North Korea.

The two journalists sentenced to hard labour in 2009 stayed in a guest house instead of a labour camp due to medical concerns.

Ali Lameda, a member of Venezuela's Communist Party and a poet invited to the North in 1966 to work as a Spanish translator, said that he was detained in a damp, filthy cell without trial the following year after facing espionage allegations that he denied. He later spent six years in prison after a one-day trial, he said.

Photo: A South Korean man watches a television news program showing Korean American Kenneth Bae at the Seoul Railway Station in Seoul, South Korea, Thursday, May 2, 2013. Bae detained for six months in North Korea has been sentenced to 15 years of hard labor for "hostile acts" against the state, the North's media said Thursday — a move that could trigger a visit by a high-profile American if history is any guide. (Photo by AP Photo/Ahn Young-joon)